Until the early 20th century, eating various bits of the human body — including flesh, bone, blood and even the various types of moss that grow on human skulls — was widely accepted as an approved medical therapy.

Flesh from a mummified body was thought to be an excellent remedy for bruising. Powdered mummy, known as "mummia" was still included in the Merck Index of chemicals until the early 1900s.

In popular culture, you might remember the fairy tale children Hansel and Gretel — in which an evil witch fattens the children up to eat them.

Cannibalism has been well documented over the last few centuries as happening in most parts of the world — and not just in so-called primitive or tribal societies.

Historic cannibalism in the West

In the US, the Donner Party of westward pioneers found themselves stranded by snow in a high mountain pass in California in 1846 and 1847. The survivors survived by eating human flesh.

There were many cases of cannibalism in the Second World War, most notably in prisoner of war camps and during the Siege of Leningrad.

In 1972, Uruguayan Air Force Flight 571 crashed in the Andes. The survivors were rescued after 72 days, but they had resorted, in desperation, to eating those who had already died.

Even today, some practice placentaphagy: the eating of the placenta after a child has been born.

Types of cannibalism

One classification of cannibalism breaks it down into endocannibalism — where a person from within the community is eaten — and exocannibalism — where the person consumed is from outside.

Endocannibalism is usually associated with rituals: the grieving process after the death of a tribe member, ensuring the souls of the dead make it into the bodies of the next generation, respect and honour, and so on.

Exocannibalism is usually associated with hostility, violence, contempt and celebration of victory.

In both endocannibalism and exoannibalism, there is generally some degree of belief that the eating of another's flesh will give the cannibal some of the victim's desirable characteristics.

Another way to describe different types of cannibalism is to consider the activity's function or motivation.

In this rubric, nutritional cannibalism looks at eating flesh in terms of its nutritional value or taste.

Ritual or magical cannibalism relates to religious beliefs.

Survival cannibalism happens as a last resort to keep some of a group alive, when there is not enough food to keep the whole group alive.

And of course, there is psychotic or criminal cannibalism.

The questionable nutritional value of humans

As it turns out, human flesh is not particularly nutritious.

Consider the mammoth, which we wiped out about 5,000 years ago. Its skeletal muscle offers about 15 million kilojoules.

By the same token, a horse would deliver about 840,000 kJ. A human body, on the other hand, has a potential of only 134,000 kJ.

So a mammoth would keep a modern human alive for over 1,700 days, a horse for 96 days, but eating another human would give you only 15 days.

Maybe nutrition isn't the only reason we humans have such a long history of cannibalism. After all, in Western societies, taboos against cannibalism have gradually been established over the last century.

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